IgA nephropathy (IgAN) is one of the most common primary diseases of the glomeruli. In Europe, it accounts for up to 30% of all primary glomerulopathies. Berger’s disease is characterized by different rates of progression, in some cases leading to endstage renal failure. IgAN has a multifactorial pathogenesis and a different role is also attributed to various genes. At present, histopathological examination of the kidney biopsy specimen is necessary to make a diagnosis. This publication will discuss the genetic basis and diagnostics of IgA nephropathy.